if something is profitable people will want more and invest more
those that dont upgrade/expand their hardware get left behind
That's the perfect truth, the mining sector is profitable and since the sector is not monopolized or institutionalized it's open to everyone to try it out and see the outcome.
And just like in every competition those who are more advanced in their equipment definitely tends to be the big fishes in the pond, and just like you said no matter the stage of mining was or would get what would remain constant in competition.
The bitter Truth now to miners of Bitcoin is that if you don't have the resources to compete right now it's been to avoid it, was watching a Bitcoin mining center the other day and was impressed with the financial effort put into it by the miner, even at that he is still going to have to compete now what are your chances with low Capital and finances?